1. Field of the Invention
The present invention relates to a method for executing a navigation software, and more particularly, to a method for automatically executing a navigation software and loading the map data based on the received longitude/latitude data while the Global Positioning System (GPS) is activated.
2. Description of the Related Art
In 1973, the US Department of Defense started developing a precise satellite navigation and positioning project, called Global positioning system (GPS), which would cost over 12 billion US dollars and take more than 20 years. The first GPS satellite was launched in 1978, and 3D, all-weather positioning operation has been formally introduced since October 1993. The development of the GPS is only for supporting the military aviation and airplane requirements. Thus, the GPS user can receive signals from 4˜8 satellites anytime and anywhere on the earth simultaneously for positioning the current location in any weather condition if not blocked by any landform or construction.
GPS is mainly composed of three segments as follows.
1. Space satellite segment: this segment is composed of 24 satellites running in 6 orbits 20200 KM above the earth and circulating the earth once about every 12 hours. Each satellite continuously transmits radio waves carrying orbit data and timing information of the satellite to be applied by various receivers on earth.
2. Ground control segment: this segment is mainly the ground control station configured for tracking and controlling the satellite operations mentioned above. It is mainly responsible for modifying and maintaining various parameter information required for normal operation of each satellite, such that each satellite is certain to provide accurate information to be received by the user's receiver.
3. User receiver segment: this segment is configured to track all GPS satellites and to calculate a coordinate of current location, a moving speed, and a timing of the receiver in real time, and the GARMIN GPS belongs to this segment. Only the third segment can be owned and applied by the public. The calculation is based on the following theory: when the satellite is running in the air above the earth, there is a corresponding coordinate value to represent its current location (i.e. a known value), while the coordinate value of the receiver's location is unknown. The time spent in transmitting the message sent by the satellite is calculated by comparing the satellite's clock with the receiver's clock, and the distance between the satellite and the receiver is obtained by multiplying the time difference mentioned above by an electric wave transmission speed (i.e. the light speed), such that a correlated equation can be generated based on the triangle vector relationship.
The GPS is becoming more popular now. People like to carry an electronic device supporting the GPS function while traveling, and the electronic device may store a navigation software and a set of map data for multiple countries or the area (such as a certain state or province) of a specific country. Therefore, it would come in handy when the user rents a car in a specific country trying not to get lost. However, when the user is crossing through states or provinces, they might have to stop the car and manually execute the navigation software and the map data according to the current location, which is very time consuming and not user friendly. In addition, if the user is not familiar with the geographic location, he would be not sure which navigation software and the map data to use with the current location.